The present invention relates to acrylic curable compositions and more specifically to such compositions of improved flexibility based upon dicyclopentenyl oxyethyl methacrylate (hereinafter DOMA).
A variety of applications for acrylic curable compositions require formulations of low toxicity which are highly flexible, yet possess adequate hardness so that such compositions are practical for everyday use. Such applications include orthopedic castings, bone cement, dental applications, encapsulants, embedments, potting compositions, and the like. Toxicity restrictions are necessary so that safe handling of the acrylic compositions can be practiced at the manufacturing plant. Also, for medical and dental applications even more toxicity restrictions are placed on the compositions for efficacy in use. Another desirable attribute of such acrylic curable compositions is that they cure very rapidly, often in the absence of oxygen. Quick set-up and cure at room temperature protects the patient in medical applications and minimizes damage to electrical components when encapsulation of such components is practiced. Other applications require quick cure times at low temperatures as will be apparent to those skilled in the art.
Dicyclopentenyl oxyethyl methacrylate, or DOMA, is an unusual monomer containing acrylic unsaturation and non-aromatic ring unsaturation. Different curing systems can be employed using DOMA. For example, U.S. Pat. No. 3,642,750 proposes the use of various acrylic-substituted dicyclopentadienes as the basis for anaerobic adhesive compositions. More recently, Emmons in "Recent Developments in Oxidative Polymerization", preprints of papers presented at the National Symposium on Polymers in the Science of Man, pp 167-172 (June 9-11, 1980), proposes a variety of uses for acrylic compositions based on DOMA. Emmons notes that the oxyethyl linkage in DOMA provides a monomer which does not suffer from unacceptable noxious odors as did some of the acrylic-substituted dicyclopentadiene monomers in the past.